JPH11180737A - Antifogging film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film having excellent durability which prevents fog only by adhering the film to a window glass or the like by forming a ceramic transparent hydrophilic coating film which has no photocatalytic function and which consists of oxides of silicon, aluminum, zirconium or the like on the surface of a transparent synthetic resin film, and then forming a transparent adhesive layer to the back surface. SOLUTION: As for the synthetic resin film, a polyester or acryl resin is preferably used because it has good adhesiveness with an adhesive, and the thickness of the film is 7 to 100 μm, preferably 12 to 30 μm. The hydrophilic coating film consists of a transparent ceramic material having no photocatalytic function and consists of, for example, silicon dioxide, aluminum oxide and zirconium oxide. The hydrophilic coating film is preferably formed to 10 to 1000 Åthickness, especially 50 to 100 Å, by physical vapor deposition such as vacuum vapor deposition, sputtering, arc discharge and ion beam method. Especially, sputtering is preferably used. Then a transparent pressure-sensitive cohesive adhesive layer is formed on the back surface of the synthetic resin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifogging film, which is used to prevent fogging by attaching it to the surface of a vehicle or other window glass or a mirror.

[0002]

2. Description of the Related Art In order to prevent fogging of windowpanes and mirrors, an antifogging film is formed on the surfaces of windowpanes and mirrors by spraying a liquid containing a surfactant or titanium oxide, or hot air is blown. Drying has been done. However, the antifogging film formed by spraying has a drawback that it has poor durability and easily runs off, and the method of blowing hot air requires a hot air blowing device, which is not easy to install, and There were problems such as the need for space.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a film which can be prevented from fogging simply by being attached to the surface of a window glass or a mirror.
An object of the present invention is to provide an anti-fog film that does not require a mounting space.

[0004]

The antifogging film according to the present invention comprises a transparent synthetic resin film having a transparent hydrophilic film made of ceramics having no photocatalytic function on the surface and a transparent adhesive layer on the back surface. Is provided.

[0005] The above antifogging film is provided to a user with a release paper layered on the surface of the pressure-sensitive adhesive layer, cut into a desired size, and then peeled off the release paper to cover the surface of a window glass or a mirror. Used by crimping. In this case, since the synthetic resin film, the hydrophilic coating on the front surface, and the pressure-sensitive adhesive layer on the back surface are transparent, the functions of the window glass and the mirror are not impaired. And since the surface of the synthetic resin film is covered with a hydrophilic coating,
The moisture in the air flows down while being held by the hydrophilic coating without dew condensation, and the film is maintained in a transparent state. Moreover,
Since the hydrophilic coating does not have a photocatalytic function, it does not activate oxygen in the air by receiving light, so it does not attack the synthetic resin film with active oxygen, and since the hydrophilic coating is ceramic, It does not disappear by use and has excellent durability.

The above-mentioned synthetic resin film is preferably a film made of polyester or acrylic resin from the viewpoint of good adhesiveness with an adhesive. Especially polyester film,
This is preferable because a hydrophilic film can be easily formed by sputtering described later. And the thickness of this film is 7 ~ 100μ
m, particularly preferably 12 to 30 μm, and if it is less than 7 μm, it is too thin to make it difficult to handle, while if it is more than 100 μm, it is too thick to lower the transparency and it becomes difficult to stick it on a curved surface.

The above-mentioned hydrophilic film is a transparent ceramic film having no photocatalytic function and is made of an oxide of silicon, aluminum or zirconium, ie, silicon dioxide.
Examples are aluminum oxide and zirconium oxide. And the thickness of this hydrophilic coating is 10 to 1000
Å, particularly preferably 50 to 100 、, and this thickness is 10 Å
If it is less than 1, the desired antifogging effect cannot be obtained, and conversely,
If it exceeds, only cost rises and it is uneconomical.

The above-mentioned hydrophilic film can be formed by physical vapor deposition such as vacuum vapor deposition, sputtering, arc discharge and ion beam method.
This is preferable in that the strength of the obtained film is high and the film is not easily peeled off.

At the time of sputtering, a synthetic resin film is spread and placed in a closed chamber, and an anode and a target are arranged so as to face the surface so that the anode is located between the film and the target. However,
The target is made of silicon, aluminum or zirconium in a plate shape in advance. Then, the inside of the closed chamber is decompressed to a vacuum of about 5 × 10 ⁻⁵ Torr, and an inert gas such as argon is introduced to introduce a pressure of 5 × 10 ⁻⁵ Torr.
An inert gas atmosphere of about ^-4 Torr is formed, and then oxygen is introduced to form a mixed gas atmosphere of argon and oxygen at a pressure of about 2 × 10 ^-3 Torr.

[0010] Thereafter, 5 Å between the anode and the target.
A glow discharge is generated by applying a DC voltage of 00 to 1000 V, and the generated argon ions collide with the target to strike out silicon, aluminum or zirconium from the target, and scattered toward the film with oxygen in the mixed gas. The oxidized silicon dioxide, aluminum oxide or zirconium oxide is deposited on the surface of the film and quenched to form a hydrophilic film having an amorphous structure. Note that the target may be made of silicon dioxide, aluminum oxide, or zirconium oxide, and sputtering may be performed in an inert gas atmosphere.

The above-mentioned film is cooled from the back side with a water-cooled cylinder or the like to reduce the temperature of the film to a softening temperature (Celsius).
/ 2 or less. Further, it is preferable that the target is also cooled by water cooling or other cooling means, or heat is easily radiated. In addition, a long film can be wound in a roll shape and sputtering can be continuously performed while being drawn at a predetermined speed.

The pressure-sensitive adhesive layer provided on the back surface of the synthetic resin film only needs to be tacky (pressure-sensitive) and transparent, and in particular, a layer that can be peeled off after application and reused is preferable. Examples of such pressure-sensitive adhesives include emulsion-type pressure-sensitive adhesives such as urethane-based, acrylic-based, and vinyl acetate-based adhesives. The coating thickness is preferably 1 to 10 μm in solid content.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 10 denotes an anti-fogging film, which has a thickness of 10 to 30 .mu.m and has a hydrophilicity of 50 to 100 DEG made of silicon dioxide adhered by sputtering to the surface of a polyethylene terephthalate film F. A coating 11 is provided, and a pressure-sensitive adhesive layer 12 made of an emulsion-type acrylic pressure-sensitive adhesive is provided on the back surface. A release paper 13 is overlaid on the pressure-sensitive adhesive layer 12.

FIG. 2 is a longitudinal sectional view showing an example of a sputtering apparatus. A flat plate-like target 21 made of silicon is fixed on a hollow target source 22 with its surface upward at the lower part of a chamber 20 which can be closed. The target 21 is cooled from below by the cold water passed through the target source 22. Anodes 23 are horizontally installed above and below the target 21, and a direct current power supply E supplies 500 to 100
A DC voltage of 0 V is applied.

A water-cooled cylinder 24 is horizontally and rotatably installed above the anode 23, and a delivery shaft 25 for the unprocessed polyethylene terephthalate film F is provided at the upper right, and a water-cooled cylinder 24 for the processed film F is provided at the upper left. The winding shafts 26 are installed horizontally and rotatably, respectively.
The unprocessed film F wound around the delivery shaft 25 is drawn out, wound around the water-cooled cylinder 24 via the upper right guide roller 27, and wound up on the winding shaft 26 via the upper left guide roller 28. A vacuum pump 29, a gas cylinder 30 for supplying argon gas, and an oxygen cylinder 31 for supplying oxygen are connected to the chamber 20, respectively.

In the above apparatus, the film F is cooled by the water-cooling cylinder 24 while rotating the feed shaft 25, the winding shaft 26 and the water-cooling cylinder 24 while feeding the film F at a predetermined speed in the clockwise direction. Maintain below 60 ° C. On the other hand, the vacuum pump 29 is driven to drive the chamber 20.
The internal pressure is reduced to about 5 × 10 ⁻⁵ Torr, then argon gas is introduced from a gas cylinder 30 to adjust the internal pressure of the chamber 20 to about 5 × 10 ⁻⁴ Torr.
Pressure from the chamber 20 to 2 × 10 ^-3 To
rr, and then a DC voltage of 500 to 1000 V is applied between the anode 23 and the target 21 to cause silicon to fly out of the target 21 and react with the oxygen in the chamber 20 to form silicon dioxide. ,
This silicon dioxide is adhered on the film F to form a hydrophilic film 11 having an amorphous structure. At this time, the thickness of the hydrophilic coating 11 is adjusted to 50 to 100 ° by adjusting the feeding speed of the film F.

When the sputtering process is completed, the processed film F is taken out from the chamber 20 together with the take-up shaft 26, the processed film F is drawn out from the take-up shaft 26, and guided to a roll coater. The resin adhesive has a solid content thickness of 1 to 10
It is applied to a thickness of μm, dried, and a release paper is laminated on the applied surface to obtain a product. In addition, when sputtering,
When aluminum or zirconium is used for the target 21, the hydrophilic coating 11 of aluminum oxide or zirconium oxide is obtained. Further, the film F after the sputtering process may be overlaid on release paper coated with the above-mentioned adhesive.

[0018]

EXAMPLES An antifogging film was produced by the method of the above embodiment. That is, the synthetic resin film F has a thickness of 25 μm.
m of a polyethylene terephthalate film having a thickness of 80 ° and a hydrophilic film 11 of silicon dioxide on the surface thereof.
Was formed by sputtering, an emulsion-type acrylic resin-based pressure-sensitive adhesive was applied to the back surface, and dried to form a pressure-sensitive adhesive layer 12 having a thickness of 5 μm.

When the obtained antifogging film 10 was cut into the size of a window glass of a house, the release paper was peeled off and affixed to the inner surface of the window glass. Also, no fogging occurred in winter. On the other hand, the other window glass fogged due to dew condensation.
Also, when used in the rain by attaching it to a side mirror of a passenger car, the side mirror did not fog and a good visual field was obtained. In addition, when the above antifogging film 10 was used by attaching it to a mirror in a bathroom, it was not fogged by steam and a good reflection image was obtained. In any case, no functional deterioration occurred during the test period of 90 days.

[0020]

As described above, the anti-fogging film of the present invention is cut into a desired size, and is adhered to a window glass, a mirror, or the like of a house or an automobile, thereby preventing the fogging and brightening the film. A good field of view or a reflected image can be obtained, and further, it does not require a mounting space, has excellent durability, and can be peeled off and re-attached as needed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an antifogging film.

FIG. 2 is a sectional view showing an example of a sputtering apparatus.

[Explanation of symbols]

F: Synthetic resin film 10: Anti-fogging film 11: Hydrophilic coating 12: Adhesive layer 13: Release paper 20: Sputter chamber 21: Target 22: Target source 23: Anode 24: Water-cooled cylinder 25: Delivery axis 26: Winding shaft 29: Vacuum pump 30: Gas cylinder 31: Oxygen cylinder

Claims (4)

[Claims] 1. An anti-fogging film comprising a transparent synthetic resin film having a transparent hydrophilic film made of ceramics having no photocatalytic function on the surface and a transparent adhesive layer on the back surface. 2. The antifogging film according to claim 1, wherein the hydrophilic coating comprises an oxide of silicon, aluminum or zirconium. 3. The antifogging film according to claim 2, wherein the hydrophilic film is a sputtered film having a thickness of 10 to 1000 °. 4. The synthetic resin film has a thickness of 7 to 100 μm.
The antifogging film according to any one of claims 1 to 3, which is a polyester film.